A. Field of the Invention
This invention relates generally to an improvement in illumination devices such as electronic timepieces equipped for a conventional analog or digital display, indicator gauges, which may comprises a meter panel, directional gauges, used for example in motor vehicles, ornamentation displays of an image, logo or design, and other similar articles which are illuminated for viewing under poor lighting conditions.
B. Description of the Prior Art
Historically, watches, gauges and other similar articles were first illuminated by using phosphorescent markings. However, when both the manufacturing methods of phosphorescent materials and the materials themselves proved to be medically and environmentally unacceptable, other illuminating means were developed. Some of these other means include the use of LED, LCD, and fluorescent devices, as well as incandescent bulbs. All of these proved to be unsatisfactory, especially for small devices such as wrist watches.
Additionally, these devices could not provide sufficient illumination due to a non-uniformity in brightness across the illuminated display surface. The insufficient illumination was the result of the positioning or shape of the light source itself which was either a point or linear source thereby making these illumination devices limited and unacceptable.
Recently, electroluminescent lighting, hereinafter referred to as EL, was introduced, for an analog or digital watches as another known alternative. An EL element is positioned underneath the watch dials, or other surfaces, or alternatively the dials themselves are made of an EL material, as described in U.S. Pat. Nos. 3,749,977xe2x80x94Sliker, 4,775,964xe2x80x94Alessio and Olsen, 4,208,869xe2x80x94Hanaoka, 5,029,046xe2x80x94Kameda, 5,117,334xe2x80x94Kameda. In all of these references direct illumination is provided upward towards the viewer, restricting any aesthetic aspects such as a full color logo or colored images on the dial. Another disadvantage of EL""s is that they require complicated auxiliary circuitry. Moreover, the lighting colors are determined by phosphorus contents of the EL, and are limited commercially to colors such as blue-green, white and yellow.
U.S. Pat. No. 5,997,161 discloses a black light instrument cluster illuminated by standard black light or UV bulbs.
U.S. Pat. Nos. 5,962,971 and 5,813,753 disclose complicated means of generating UV light.
In my U.S. Pat. Nos. 6,106,127 and 6,299,321, incorporated herein by reference, I have described an illumination device for a watch and other instruments consisting of a light emitter disposed on a transparent or translucent surface(like the a watch crystal). The emitter receives power from a battery disposed in the watch case through wires imbedded in, or otherwise attached to the crystal. The emitter is adapted to emit light in a wide angle to illuminate the dial of the watch in an even light distribution pattern. The following concepts comprise various improvements to the basic patented invention of the these patents.
It is, accordingly, an objective of the present invention to eliminate the above-mentioned disadvantages encountered in the prior art and provide an improved system through which sufficient illumination can be provided to both indicia of interest as well as logos and other decorative elements.
It is another objective of the present invention to provide an improved illumination device for an electronic or analog timepiece, indicator gauge, directional gauge or ornamental device or other articles eliminating any EL as the illumination source and its associated circuitry.
Another objective of the invention is to provide an improved illumination apparatus for viewing the dial or surface of various objects by positioning an illumination device to direct light in a direction towards the subject to be illuminated which makes viewing easier, more efficient and less stressful to the viewer.
A further objective of this invention is to provide in situations such as limited lighting or at night time, the cosmetic illumination of single or multiple color images, logos or items located on or about the surface of a timepiece, indicator or directional gauges or ornamentation devices.
A further objective is to provide a solid state illumination device that makes use of a source of UV light to provide a novel type of illumination for watches, gauges and other similar articles.
The present invention seeks to attain these objectives by disposing a light-emitting element, on or inside a light transmissive surface of the article to be illuminated. This element is positioned in the center, sides or in a random placement and rendered light emisive or is activated by means of an electronic circuit which is installed within or in proximity of said article. An illumination switch controlled by an external control member is provided on the case of the article for selectively activating the light emitting element.
More particularly, the light source is disposed either on an inner surface of, or is imbedded within the cover or article itself, in such a manner that is virtually invisible to the viewer.
In many instances various objects must be observable in the dark or under low lighting conditions. In instances where it is not possible, or it is inconvenient to provide full illumination, low level lighting is provided to light the observed object either directly, laterally, using edge-effect type lighting or using backlight type illumination (wherein the light source is built into or disposed behind the object to be observed). However, these solutions have been found to be unsatisfactory because they provide mediocre lighting at best. Moreover, in many instances these types of devices are not pleasing esthetically.
For example, most automobiles, motorcycles or aeronautical vehicles use some form of interior and/or instrument illumination for visibility at night or in low visibility conditions. This illumination system is usually based on electroluminescent (EL), incandescent or LED devices which require special controls, power supplies, dimmers and so on.
Another example where improved illumination would be useful are laptop computers. Under poor lighting conditions most laptops (as well as PDAs, cell phones, electronic games and other similar small hand-held devices) have built-in light sources or active screens that are fairly easy to see. However, the keyboards and controls for these devices are provided with little or no illumination and accordingly they are very hard to see.
One effective means of lighting objects comprise so-called black lights. These kind of lights are particularly desirable for providing illumination under low lighting conditions and are especially useful when used in combination with fluorescent inks or objects having fluorescent colors applied on the object being illuminated. However, until now, all black light sources comprised high voltage tubes or incandescent lamps that have been coated with a filter adapted to transmit UV light and block most visible light. Typically these filters do allow a small amount of light to escape from the tube in the violet range so that the light can be seen with the naked eye when turned on.
Similarly, a UV light source can be used for a laptop or standard compute keyboard. This light source could be an accessory or built into the unit. As an accessory the unit could be connected and powered through a USB port and could be fixed or could be provided on a flexible support so as to allow the user to customize the position of the light source. The light source could have an on/off switch, which could allow the user to activate the light source as desired.
As an integrated unit within the keyboard or on the periphery it is the UV light sources positioning which is critical for maximum illumination. Under the most efficient circumstances a single UV-LED light source could be positioned above the illuminated object at a predetermined distance for effective illumination but in manner that insures that it will not interfere with the users vision or periphery. The UV light source could be made to provide a broad radial pattern over the entire area or modified with a directional cone or shield focusing the light to the desired area for illumination.
Inks or other materials responsive to UV light (such as fluorescent and phosphorescent inks etc.) are applied onto or processed into the keyboard, mouse or the desired illuminated area and could be make into shapes, diagrams, logos, images or numerals in multiple colors such as red, green, yellow, orange, blue, purple or pink.